1. Field of the Invention
This present invention relates to a printer and a printing method, and more particularly, is suitably applied to a printer and a printing method for printing a color image based on input print data on a printing medium.
2. Description of the Related Art
This type of printer can perform image adjustment processing, such as color adjustment and lightness adjustment, on a color image based on print data, which is supplied from a personal computer in accordance with operations by an operator, by applying predetermined signal processing to the print data.
In actual, in the case where, for example, the color adjustment out of the above described image adjustment processing is performed, this printer can fine-adjust the tint of a color image by changing levels of primary color signals for red (R), green (G), and blue (B) forming print data, in accordance with the adjustment by an operator.
In general, rising signal levels of three primary colors has a characteristic that colors (red, green, blue) shown by primary color signals are emphasized, and lowering the signal levels has a characteristic that complementary colors (cyan, magenta, yellow) of colors shown by the primary color signals are emphasized.
However, for an operator who adjusts a color image based on print data to a desired tint different from the present tint in the above described color adjustment, it is difficult to determine which color should be selected among three primary colors and further, how much a signal level of a selected color should be changed. Therefore, the operator actually adjusts the present tint to a desired tint by his intuition.
As one method of solving the above described problems, a printer is proposed which is configured so that whenever the image adjustment processing are updated in accordance with operations by an operator, the updated image adjustment is reflected on a color image and the reflected result can be output as a video signal to a monitor which is connected as an external unit. Thereby, the operator can perform the above described image adjustment processing while visually confirming a color image based on the video signal displayed on the monitor.
Since a method of mixing colors using the additive process is applied to the above described color image based on a video signal displayed on a monitor and a method of mixing colors using the subtractive process is applied to a color image actually printed on a printing medium, a tint of a color image subjected to image adjustment processing may slightly differ between the case where the color image is displayed on a monitor and the case where the color image is actually printed on a printing medium.
For example, since the Japanese skin color is comprised of red, green, and blue with a higher ratio in this order among three primary colors, raising a blue signal level actually makes the skin color pinkish, not bluish, and lowering a red signal level actually makes the skin color yellowish and whitish, not cyanic (light bluish). This is the reason why the color adjustment processing is very difficult.
An operator purposes obtaining a printing medium having a color image printed thereon, and a color image actually printed on the printing medium frequently has a tint different from a tint desired by the operator even if the above described color adjustment processing is performed on the basis of a color image displayed on a monitor. In this case, it is necessary to repeat the above described color adjustment processing many times until the tint desired by the operator is obtained and further, the operator has to print the color image whenever the color adjustment is performed, in order to visually confirm the tint. As a result, problems occur that the printing medium is wasted and the time also wastefully elapses.